A simple typo in an XML domain file could lead to a crash, because we called STRPREFIX() on the looked up value without checking it was non-null. Patch is trivial, and should go in but I wonder if we shouldn't make those STR macros safer too like turning #define STRPREFIX(a,b) (strncmp((a),(b),strlen((b))) == 0) into #define STRPREFIX(a,b) ((a) && (b) && (strncmp((a),(b),strlen((b))) == 0)) anyway I think we should apply the patch independently, without it libvirtd crash, with it we get the proper error report: [root@paphio ~]# virsh define RHEL-5.4-64.xml 18:32:21.982: warning : processCallDispatchReply:7570 : Method call error error: Failed to define domain from RHEL-5.4-64.xml error: internal error No <source> 'dev' attribute specified with <interface type='bridge'/> Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel(a)veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/